Collapsible anvil plate assemblies for circular surgical stapling devices

ABSTRACT

Circular stapling instruments and anvil assemblies. The anvil assemblies may have collapsible anvil support members that may be inserted through an opening in a patient and then expanded to be attached to an anvil plate assembly that has a staple-forming surface thereon. The anvil support member is attachable to the anvil plate assembly in such a way that when the anvil assembly is coupled to the stapling head of a circular stapler, the staple-forming surface is in substantial registry with the staples supported in the stapling head. A variety of different anvil support members and anvil plate assemblies are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional patent application claims the benefit of andpriority from U.S. Provisional Patent Application Ser. No. 61/452,432,filed Mar. 14, 2011, entitled “Surgical Stapling Instruments”, theentire disclosure of which is hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention generally relates to surgical procedures andsurgical instruments for completing such procedures, and moreparticularly, to surgical stapling devices and methods of use.

BACKGROUND

Obesity is one of the fastest growing health problems in the world. Forexample, the Center for Disease Control estimates that over 20% of theU.S. population is obese. Gastric bypass surgery has been found to beone of the most effective treatments for morbid obesity.

Several different gastric bypass surgeries exist. The most commongastric bypass surgery is a Roux-en-Y gastric bypass. In a Roux-en-Ygastric bypass, the stomach is made smaller by creating a small pouch atthe top of the stomach using surgical staples. The smaller stomach isconnected to the middle portion of the small intestine (jejunum),bypassing the rest of the stomach and the upper portion of the smallintestine (duodenum). The procedure can be done by making a largeincision in the abdomen (an open procedure) or by making a smallincision and using small instruments and a camera to guide the surgery(a laparoscopic procedure). Laparoscopic procedures generally result inquicker recoveries and shorter hospital stays. The risk associated withwound infection is significantly reduced and patients generally reportless pain and experience a quicker return to normal activity.

When performing Roux-en-Y gastric bypass surgery laparoscopically, anumber of conventional trocar devices are placed in various locationsthrough the abdominal wall to provide passages through which surgicalinstruments, grasping devices and cameras may be inserted. As indicatedabove, such procedure involves the creation of a small stomach pouch andthe attachment of the jejunum thereto by means of an anastomosis(commonly referred to as the G-J anastomosis). The jejunum portion isthen reattached to the middle portion of the jejunum by anotheranastomosis (commonly referred to as the J-J anastomosis). Sucharrangement therefore bypasses the severed portion of stomach andduodenum.

The circular stapler is an essential tool for construction ofgastrointestinal anastomosis. Circular staplers useful for performingsuch procedures are disclosed, for example, in U.S. Pat. Nos. 5,104,025;5,205,459; 5,285,945; and 5,309,927 which are each herein incorporatedby reference in their respective entireties. In general, a conventionalcircular stapler typically consists of an elongated shaft that has aproximal actuating mechanism and a distal stapling mechanism mounted tothe elongated shaft. The distal stapling mechanism commonly consists ofa fixed stapling cartridge that contains a plurality of staplesconfigured in a concentric circular array. A round cutting knife isconcentrically mounted in the cartridge interior to the staples foraxial travel therein. Extending axially from the center of the cartridgeis a movable trocar shaft that is adapted to have a staple anvilremovably coupled thereto. The anvil is configured to form the ends ofthe staples as they are driven into it. The distance between a distalface of the staple cartridge and the staple anvil is commonly controlledby an adjustment mechanism that is mounted to the proximal end of thestapler shaft for controlling the axial movement of the trocar. Tissuethat is clamped between the staple cartridge and the staple anvil issimultaneously stapled and cut when the actuating mechanism is activatedby the surgeon.

When using conventional circular staplers to perform Roux-en-Y gastricbypass surgery, the anvil of the device is placed transabdominallythrough an enlarged port site and passed through a gastrotomy on theanterior aspect of the stomach. The gastric pouch is constructed aroundthe anvil and the gastrotomy is closed. The staple head of the circularstapler is inserted through the upper portion of the jejunum portion andthe anvil is connected thereto. The stapler is then “fired” to createthe anastomosis. Such method has been adopted by many surgeons. However,some drawbacks exist, including the need to enlarge the trocar site toaccommodate the anvil and the construction of the gastrotomy and itsclosure. Such additional steps undesirably lengthen the time needed tocomplete the surgical procedure.

Thus, the need exists for a circular stapling device with an anvilarrangement that can puncture through gastric walls in an unexpandedstate and then moved to an expanded state to facilitate formation of theanastomosis when the surgical stapler is actuated.

Such circular stapling devices are also commonly employed to removeddiseased portions of the colon. Introduction and management of thecircular stapler anvil into a conventional laparoscopic approach forcolorectal surgery has been an ongoing limiter to employing laparoscopicprocedures and techniques to complete such procedure. For example,laparoscopic colorectal procedures may be generally cumbersome toperform due to the number of steps involved. Such procedures are alsocomplicated by the need to avoid crossing staple lines. Other problemsthat may be encountered with such procedures involve seeding fromsubject tissue removal, the need to create one or more ports for theintroduction of anvils into the body cavity and the creation of colondefects that result from anvil placement challenges.

Thus, another need exists for a circular stapling device with an anvilarrangement that can be inserted into the patient in a collapsed stateand then reconfigured into an expanded state to facilitate formation ofthe anastomosis when the surgical stapler is actuated.

The foregoing discussion is intended only to illustrate some of theshortcomings present in the field of the invention at the time, andshould not be taken as a disavowal of claim scope.

BRIEF SUMMARY

In connection with general aspects of various embodiments of the presentinvention, there is provided an anvil assembly for a surgical staplinginstrument. In various forms, the anvil assembly comprises a pluralityof anvil plates that are movably coupled together for selective movementbetween a collapsed orientation and an expanded orientation. Theplurality of anvil plates form at least a portion of a substantiallyplanar anvil plate assembly when they are in the expanded orientation.An anvil expansion member is movably supported relative to the pluralityof anvil plates and is selectively movable between a first unactuatedposition to a second position wherein the anvil expansion member movesthe plurality of anvil plates to the expanded orientation. The anvilassembly further has a tissue-piercing tip portion.

In connection with yet another general aspect of one form of the presentinvention, there is provided a circular surgical stapling device. In oneform, the device comprises a staple cartridge that operably supports aplurality of surgical staples therein. The device further comprises atrocar shaft that has a tissue-piercing tip formed thereon. The trocarshaft being selectively axially movable relative to the staplecartridge. The device further includes an umbrella-like anvil assemblythat is movably supported relative to the staple cartridge. Theumbrella-like anvil assembly comprises a plurality of anvil platesegments that are movably supported relative to each other for selectivemovement from a collapsed orientation to an expanded orientation inresponse to an application of actuation motion applied thereto by thetrocar shaft. The plurality of anvil plate segments form an annularanvil plate assembly that is supported in substantial confrontingrelationship with the staple cartridge when the anvil assembly is in theexpanded orientation.

In accordance with still another general aspect of one form of thepresent invention, there is provided a surgical procedure for forming ananastomosis. In one form the procedure comprises providing a circularstapler that has a staple cartridge end with an anvil attached theretothat is selectively movable between a collapsed configuration and anexpanded configuration. The procedure further comprises orienting theanvil in a collapsed orientation and inserting the staple cartridge endwith collapsed anvil attached thereto through an opening in a patient.The procedure additionally comprises piercing through target tissuesthrough which the anastomosis is to be formed with the staple cartridgeend with anvil attached thereto and expanding the anvil such that thetarget tissues are located between the expanded anvil and the staplecartridge end. Additionally the procedure comprises firing the staplerto drive surgical staples supported in the staple cartridge into formingcontact with the expanded anvil and removing the staple cartridge endwith an anvil attached thereto from the patient.

In accordance with a general aspect of one form of the presentinvention, there is provided an anvil plate for a surgical staplinginstrument. In various forms, the anvil plate comprises a plurality ofanvil plate segments that are movably interconnected and reconfigurablefrom a first orientation wherein the anvil plate segments may beinserted through a cannula opening as a unit and then reconfigured intoa second orientation in the form of a substantially planar anvil plateassembly that has a diameter that is larger than the cannula opening.

In accordance with another general aspect of one form of the presentinvention, there is provided an anvil for a surgical staplinginstrument. In one form, the anvil comprises a plurality of anvil platesthat are movably coupled together for selective movement betweennon-planar orientations and a substantially planar orientation whereinthe plurality of anvil plates form an annular anvil plate assembly. Theanvil further comprises an anvil support member that is configured forattachment to the anvil plate assembly to retain it in the substantiallyplanar orientation.

In accordance with a general aspect of one form of the presentinvention, there is provided an anvil for a surgical staplinginstrument. In one form, the anvil comprises an anvil plate assemblythat has a staple forming surface thereon and an anvil support memberthat is configured to move between a collapsed position and an expandedposition wherein, when the anvil support member is in the expandedposition, the anvil support member is attachable to the anvil plateassembly. In various embodiments, the anvil support member is couplableto an actuator portion of the surgical stapling instrument.

In accordance with another general aspect of one form of the presentinvention, there is provided an anvil support member for a surgicalstapling device. In one form, the anvil support member comprises a shaftthat is configured for attachment to an actuator portion of the surgicalstapling device. The anvil support member further comprises areconfigurable linkage assembly that is coupled to the shaft. Thelinkage assembly is reconfigurable from a first configuration whereinthe linkage assembly may be inserted through a cannula opening to asecond expanded configuration adapted to support an anvil plateassembly.

In accordance with still another general aspect of one form of thepresent invention, there is provided an anvil for a surgical staplinginstrument. In one form, the anvil comprises an anvil shaft that isconfigured for attachment to an actuator portion of the surgicalstapling device. The anvil shaft defines a shaft axis. A reconfigurableanvil head assembly is coupled to the anvil shaft and has an overallwidth measured along an axis that is substantially perpendicular to theshaft axis. The anvil head is reconfigurable between a first orientationwherein the overall width has a first magnitude and a second orientationwherein the overall width has a second magnitude that is greater thanthe first magnitude.

In accordance with one general aspect of one form of the presentinvention, there is provided an anvil assembly for a circular staplinginstrument. In one form, the anvil assembly comprises an annular anvilplate assembly that has a staple-forming surface thereon. An anvilsupport member is couplable to an actuator portion of the surgicalstapling instrument and is configured to selectively move between acollapsed position and an expanded position. The anvil assembly furthercomprises structures for coupling the anvil support member to the anvilplate assembly when the anvil support member is in the expanded positionsuch that when the anvil support member is coupled to the actuator ofthe surgical stapling instrument, the staple-forming surface of theannular anvil plate assembly is in substantial registry withcorresponding staples supported in the circular stapling instrument.

In accordance with another general aspect of one form of the presentinvention, there is provided a circular stapling instrument thatincludes a stapling head that supports a plurality of surgical staplestherein. A firing system operably communicates with the stapling headfor applying a firing motion to the stapling head to thereby drive thesurgical staples therefrom. The instrument further includes an anviladjustment system and an anvil assembly. In one form, the anvil assemblycomprises an anvil shaft that is configured to be attached to the anviladjustment system in a predetermined orientation. An anvil supportmember is operably coupled to the anvil shaft and is configured to beselectively moved between a collapsed position and an expanded position.The anvil assembly further comprises an anvil plate assembly that has astaple-forming surface thereon and structures configured to coupling theanvil support member to the anvil plate assembly when the anvil supportmember is in the expanded position such that when the anvil shaft iscoupled to the anvil adjustment system in the predetermined orientation,the staple-forming surface of the anvil plate assembly is in substantialregistry with corresponding surgical staples in the stapling head.

In accordance with still another general aspect of one form of thepresent invention, there is provided a method for stapling tissue thatincludes providing a circular stapling instrument that comprises astapling head that supports a plurality of surgical staples therein. Thestapling instrument further comprises a firing system that operablycommunicates with the stapling head for applying a firing motion to thestapling head to thereby drive the surgical staples therefrom and ananvil adjustment system. The method further includes providing an anvilsupport member that is selectively movable between a collapsedorientation and an expanded orientation and providing an anvil plateassembly that has a staple-forming surface thereon. In addition, themethod comprises coupling the anvil support member to the anviladjustment system when the anvil adjustment system is in the collapsedorientation and inserting the stapling head and attached anvil supportmember through an opening in a patient. The method further includesinserting the anvil plate assembly through the opening or anotheropening in the patient and orienting the anvil support member in theexpanded orientation. In addition, the method includes attaching theanvil plate assembly to the expanded anvil support member in such a waythat the staple-forming surface thereon is in substantial registry withthe surgical staples in the stapling head and that the tissue to bestapled is positioned between the staple forming surface and thestapling head and activating the firing system to drive the surgicalstaples into forming contact with the staple forming surface.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention,and, together with the general description of the invention given above,and the detailed description of the embodiments given below, serve toexplain the principles of the present invention.

FIG. 1 is a perspective view of a surgical circular stapling instrumentwith an anvil assembly embodiment of the present invention shown inphantom lines;

FIG. 2 is a partial cross-sectional view of a stapling head and anvilassembly embodiment of the present invention wherein the anvil assemblyis in a collapsed configuration for puncturing through tissue;

FIG. 3 is a partial cross-sectional view of the stapling head and anvilassembly of FIG. 2 wherein the anvil assembly is in an open or expandedconfiguration to form a substantially planar anvil plate into which thestaples in the stapling head may be fired;

FIG. 4 is a top view of the expanded anvil assembly of FIG. 3;

FIG. 5 is an exploded perspective view of a portion of the circularstapling instrument of FIG. 1;

FIG. 6 is a cross-sectional view of the circular stapling instrument ofFIG. 1;

FIG. 7 is a partial cross-sectional view of a portion of the circularstapling instrument shaft and stapling head with an anvil assemblyembodiment of the present invention attached thereto and in an expandedor deployed configuration;

FIG. 8 is a diagrammatical view depicting use of various circularstapling instrument embodiments of the present invention to perform aRoux-en-Y procedure;

FIG. 9 is a partial cross-sectional view of a portion of a circularstapling instrument shaft and stapling head embodiment of one form ofthe present invention with another anvil assembly embodiment of thepresent invention attached thereto and in an expanded or deployedorientation;

FIG. 10 is a partial cross-sectional view of another stapling head andanvil assembly embodiment of one form of the present invention whereinthe anvil assembly is in a collapsed orientation;

FIG. 11 is a partial cross-sectional view of the stapling head and anvilassembly of FIG. 10 wherein the anvil assembly is in an expanded ordeployed orientation;

FIG. 12 is a partial cross-sectional view of another stapling head andanvil assembly embodiment of the present invention being used topuncture through tissue;

FIG. 13 is a bottom perspective view of the stapling head and anvilassembly of FIG. 12 with the anvil assembly in the collapsedorientation;

FIG. 14 is a partial cross-sectional side view of the anvil assemblyembodiment of FIGS. 12 and 13;

FIG. 15 is a partial perspective view of the stapling head and anvilassembly of FIGS. 12-14 after it has punctured through tissue and hasbeen moved to the expanded or deployed orientation and wherein somecomponents thereof are shown in cross-section;

FIG. 16 is a partial cross-sectional view of another stapling head andanvil assembly embodiment of one form of the present invention after theanvil assembly has been used to puncture through adjacent targettissues;

FIG. 17 is another partial cross-sectional view of the stapling head andanvil assembly embodiment of FIG. 16 prior to commencing the firing ofstaples;

FIG. 18 is a top view of the anvil assembly embodiment of FIGS. 16 and17 in an expanded or deployed orientation;

FIG. 19 is a partial cross-sectional view of another circular staplinginstrument embodiment of the present invention coupled to the anvilassembly embodiment depicted in FIGS. 16-18;

FIG. 20 is a diagrammatic view of a portion of a patient's colon thathas a diseased portion to be removed;

FIG. 21 is another diagrammatic view of the patient's colon depicted inFIG. 20 depicting use of a stapling instrument and anvil assemblyembodiment of the present invention in connection with the removal ofthe diseased portion;

FIG. 22 is a partial side view of additional anvil assembly embodimentsof various forms of the present invention used to puncture through thecolon wall;

FIG. 23 is a side view of the colon of FIGS. 20 and 21, after thediseased portion has been removed and the ends of the colon have beenreconnected using the stapling instrument of FIG. 21;

FIG. 24 is another diagrammatic view of the colon of FIGS. 21 and 22illustrating removal of the diseased colon segment from the patient;

FIG. 25 is a bottom perspective view of another anvil assemblyembodiment of one form of the present invention in an expanded ordeployed orientation;

FIG. 26 is a diagrammatic view of an anvil plate assembly of FIG. 25 ina collapsed orientation and being inserted through a cannula portion ofa trocar device;

FIG. 27 is a bottom view of the anvil plate assembly of FIG. 26 in theexpanded planar orientation;

FIG. 28 is a top view of the anvil plate assembly of FIG. 27;

FIG. 29 is a side elevational view of an anvil support member embodimentdepicted in FIG. 25 in a collapsed orientation;

FIG. 30 is a side elevational view of the anvil support memberembodiment of FIG. 29 in an expanded or deployed orientation;

FIG. 31 is a partial cross-sectional view of an anvil plate embodimentof one form of the present invention latched to an anvil support memberembodiment of one form of the present invention;

FIG. 32 is a perspective view illustrating insertion of another anvilplate assembly embodiment of the present invention in a collapsedorientation and inserted through a trocar cannula;

FIG. 33 is a view of a first anvil plate joint embodiment employed inthe anvil plate assembly depicted in FIG. 32 and in a collapsed or openorientation;

FIG. 34 is another view of the first anvil plate joint embodiment ofFIG. 33 in the expanded or closed orientation;

FIG. 35 is a view of a second anvil plate joint embodiment employed inthe anvil plate assembly depicted in FIG. 32 in the collapsed or openorientation;

FIG. 36 is another view of the second anvil joint embodiment of FIG. 35in the expanded or closed orientation;

FIG. 37 is an enlarged, view of an end of an anvil plate segment formingthe second anvil joint depicted in FIG. 36;

FIG. 38 is a bottom view of the anvil plate assembly embodiment of FIGS.32-37 in the expanded/assembled orientation;

FIGS. 39A-F and 39AA and 39CC depict various folded or collapsedorientations of another anvil plate assembly embodiment of another formof the present invention;

FIG. 40 is a front perspective view of an expanded anvil plate assemblyembodiment depicted in FIGS. 39A-39F, 39AA and 39CC;

FIG. 40A is a back perspective view of the expanded anvil plate assemblyembodiment of FIG. 40;

FIG. 41 is a partial perspective view illustrating insertion of theanvil plate assembly embodiment of FIGS. 39 and 40 in a collapsedorientation and inserted through a trocar cannula;

FIG. 42 is a diagrammatic view illustrating insertion of another anvilplate assembly embodiment of another form of the present invention in acollapsed orientation and inserted through a trocar cannula;

FIG. 43 is an exploded perspective view of another anvil assemblyembodiment of another form of the present invention;

FIGS. 43A-43C are various views of the anvil assembly of FIG. 43;

FIG. 44 is a perspective view of another anvil support member embodimentof another form of the present invention in a collapsed orientation;

FIG. 45 is another perspective view of the anvil support memberembodiment of FIG. 44 in an expanded or deployed orientation;

FIG. 46 is a partial cross-sectional view of a stapling head and anvilassembly embodiment of one form of the present invention;

FIG. 47 is another partial cross-sectional view of the stapling head andanvil assembly embodiments of FIG. 46 with the linkage assembly thereofin a locked position;

FIG. 48 is a partial exploded assembly view of some of the components ofthe anvil assembly embodiment depicted in FIGS. 46 and 47 and a trocarshaft of a circular stapling instrument;

FIG. 49 is a perspective view of a locking sleeve and retention ring ofthe anvil assembly embodiment of FIGS. 46 and 47;

FIG. 50 is a perspective view of a locking ring embodiment of thepresent invention before being expanded;

FIG. 51 is a perspective view of the locking ring embodiment of FIG. 50after being expanded;

FIG. 52 is another cross-sectional view of the anvil assembly embodimentof FIGS. 46 and 47 prior to firing the circular stapling instrument;

FIG. 53 is a perspective view of another anvil support member embodimentof one form of the present invention in a collapsed orientation and withthe anvil cap shown in cross-section;

FIG. 54 is another perspective view of the anvil support memberembodiment of FIG. 53 in an open or expanded orientation;

FIG. 55 is a side view of a portion of the anvil support member of FIGS.53 and 54 illustrating a range of motion of the linkage bars thereof;

FIG. 56 is a top view of the anvil support member of FIGS. 54 and 55with the linkage assembly thereof in the open or expanded position;

FIG. 57 is a partial cross-sectional view of a portion of the anvil capand a linkage bar illustrating a latch configuration of at least oneembodiment of one form of the present invention;

FIG. 58 is an exploded perspective view of an anvil support memberarrangement and anvil plate assembly arrangement of various embodimentsof the present invention;

FIG. 59 is another exploded perspective view of the anvil support memberembodiment and anvil plate assembly embodiment depicted in FIG. 58;

FIG. 60 is a bottom perspective view of another anvil support memberembodiment of one form of the present invention;

FIG. 61 is a top view of an anvil plate assembly embodiment of thepresent invention;

FIG. 62 is a partial cross-sectional view of a portion of a linkage barand anvil plate assembly of FIGS. 60 and 61 prior to being coupledtogether;

FIG. 63 is another partial cross-sectional view of the linkage bar andanvil plate of FIG. 62 after being coupled together;

FIG. 64 is a bottom perspective view of another anvil assemblyembodiment of the present invention in an expanded orientation;

FIG. 65 is another perspective view of the anvil assembly embodiment ofFIG. 64;

FIG. 66 is a top view of the anvil assembly embodiment of FIGS. 64 and65;

FIG. 67 is another top view of the anvil assembly embodiment of FIGS.64-66 in a collapsed orientation;

FIG. 68 is a perspective view of the anvil assembly of FIGS. 64-67 in acollapsed orientation;

FIG. 69 is a perspective view of a portion of the anvil assembly ofFIGS. 64-68;

FIG. 70 is another perspective view of the anvil assembly of FIGS. 64-69in a collapsed orientation;

FIG. 71 is a side view of the anvil assembly of FIGS. 64-70 in thecollapsed orientation; and

FIG. 72 is another side view of the anvil assembly of FIGS. 64-71 in theexpanded orientation.

DETAILED DESCRIPTION

The assignee of the present application also owns the followingapplications which were contemporaneously filed herewith and which areeach herein incorporated by reference in their respective entireties:

U.S. patent application Ser. No. ______, filed ______, entitled“Multiple Part Anvil Assemblies For Circular Surgical Stapling Devices”,Attorney Docket No. END6926USNP2/110014;

U.S. patent application Ser. No. ______, filed ______, entitled “ModularSurgical Tool Systems”, Attorney Docket No. END6921USNP/110019;

U.S. patent application Ser. No. ______, filed ______, entitled“Specimen Retraction Devices and Methods”, Attorney Docket No.END6930USNP/110012;

U.S. patent application Ser. No. ______, filed ______, entitled “ModularOcclusion and Tissue Acquisition Mechanisms For Circular StaplingDevices”, Attorney Docket No. END6932USNP/110010;

U.S. patent application Ser. No. ______, filed ______, entitled “TissueManipulation Devices”, Attorney Docket No. END6924USNP/110018;

U.S. patent application Ser. No. ______, filed ______, entitled“Circular Stapling Devices With Tissue-Puncturing Anvil Features”,Attorney Docket No. END6926USNP3/110013;

U.S. patent application Ser. No. ______, filed ______, entitled “AnvilAssemblies With Collapsible Frames For Circular Staplers”, AttorneyDocket No. END6926USNP1/110015;

U.S. patent application Ser. No. ______, filed ______, entitled “RectalManipulation Devices”, Attorney Docket No. END6931USNP/110011;

U.S. patent application Ser. No. ______, filed ______, entitled“Surgical Access Devices With Anvil Introduction and Specimen RetrievalStructures”, Attorney Docket No. END6925USNP/110017; and

U.S. patent application Ser. No: ______, filed ______, entitled“Surgical Bowel Retractor Devices”, Attorney Docket No.END6922USNP/110009.

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those of ordinary skill in the art will understand that thedevices and methods specifically described herein and illustrated in theaccompanying drawings are non-limiting exemplary embodiments and thatthe scope of the various embodiments of the present invention is definedsolely by the claims. The features illustrated or described inconnection with one exemplary embodiment may be combined with thefeatures of other embodiments. Such modifications and variations areintended to be included within the scope of the present invention.

Reference throughout the specification to “various embodiments,” “someembodiments,” “one embodiment,” or “an embodiment”, or the like, meansthat a particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodiment.Thus, appearances of the phrases “in various embodiments,” “in someembodiments,” “in one embodiment”, or “in an embodiment”, or the like,in places throughout the specification are not necessarily all referringto the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments. Thus, the particular features, structures, orcharacteristics illustrated or described in connection with oneembodiment may be combined, in whole or in part, with the featuresstructures, or characteristics of one or more other embodiments withoutlimitation. Such modifications and variations are intended to beincluded within the scope of the present invention.

The terms “proximal” and “distal” are used herein with reference to aclinician manipulating the handle portion of the surgical instrument.The term “proximal” referring to the portion closest to the clinicianand the term “distal” referring to the portion located away from theclinician. It will be further appreciated that, for convenience andclarity, spatial terms such as “vertical”, “horizontal”, “up”, and“down” may be used herein with respect to the drawings. However,surgical instruments are used in many orientations and positions, andthese terms are not intended to be limiting and/or absolute.

FIG. 1 illustrates a circular stapling instrument 10 that may beemployed in connection with various anvil assembly embodiments of thepresent invention. The construction and operation of circular surgicalstapling instruments are generally known in the art. Thus, thoseconventional components and features of circular staplers will not bediscussed in detail herein beyond what may be necessary to understandthe construction and operation of the various embodiments of the presentinvention. As the present Detailed Description proceeds, those ofordinary skill in the art will understand that the various embodimentsof the present invention may be effectively employed with a variety ofdifferent circular stapler configurations without departing from thespirit and scope of the present invention. For example, variousembodiments of the present invention may be employed with those circularstaplers disclosed in U.S. Pat. No. 7,506,791, entitled “SurgicalStapling Instrument With Mechanical Mechanism For Limiting MaximumTissue Compression”, the disclosure of which is herein incorporated byreference in its entirety. Accordingly, the scope of protection affordedto the various embodiments of the present invention should not otherwisebe limited to use with the exemplary circular stapler depicted herein.

The circular stapling instrument 10 depicted in FIG. 1 includes astapling head 20, an anvil assembly 200, an adjustment knob assembly 40,and handle assembly 60. The stapling head 20 is coupled to the handleassembly 60 by an arcuate shaft assembly 80. A trigger 120 is pivotallysupported by the handle assembly 60 and acts to operate the stapler 10when a safety mechanism 62 is released. As will be discussed in furtherdetail below, when the trigger 120 is activated, a firing system (notshown in FIG. 1) operates within the shaft assembly 80 to cause thestaples to be expelled from the stapling head 20 into forming contactwith the anvil assembly 200. Simultaneously, a knife operably supportedwithin the stapling head 20 acts to cut tissue held within thecircumference of the stapled tissue. The stapler 10 is then pulledthrough the tissue leaving stapled tissue in its place.

FIGS. 2 and 3 illustrate one form of stapling head 20 that may beemployed in connection with various anvil assembly embodiments of thesubject invention. In various embodiments, the stapling head 20 maycomprise a casing member 22 that supports a staple cartridge 26 therein.The casing member 22 further supports a circular staple driver 24 thatis adapted to interface with the staple cartridge 26 and drive staples28 supported therein into forming contact with the anvil assembly 200 aswill be discussed in further detail below. A circular knife member 30 isalso centrally disposed within the staple driver 24. The proximal end ofthe casing member 22 may be coupled to an outer tubular shroud 82 of thearcuate shaft assembly 80 by a distal ferrule member 83.

FIGS. 5-7 illustrate one form of arcuate shaft assembly 80 that may beemployed with various circular stapling instrument embodiments of thepresent invention. As can be seen in FIGS. 5 and 7, the arcuate shaftassembly 80 may include a compression shaft 84, a distal compressionshaft portion 85, a top tension band 86, a bottom tension band 87 and aspacer band 88 that are assembled within the outer tubular shroud 82.The anvil shaft 210 of the anvil assembly 200 is attached to the toptension band 86 and bottom tension band 87 by fasteners 89. The proximalends of the top tension band 86 and bottom tension band 87 are attachedto a distal end of an adjustment shaft 90. As can be seen in FIG. 7,stapling head 20 includes a distally protruding central hub portion 100that is centrally disposed within the stapling head 20 and attached tothe shaft casing 82 at point 101. The central hub portion 100 may beattached to the shaft casing 82 by, for example, adhesive, welding,rivets, etc. The compression shaft 84 is free to move axially relativeto the central hub portion 100 to drive the staple driver 24 distally.Thus, axial movement of the compression shaft 84 within the outertubular shroud 82 causes the staple driver 24 to move axially within thecasing member 22. As will be discussed below, actuation of the firingtrigger 120 will cause the compression shaft 84 to move in the distaldirection (arrow “DD”) thereby driving the staple driver 24 distally totire the staples 28 into forming contact with the anvil assembly 200. Asthe staple driver 24 is driven distally, it also drives the distal end31 of the knife 30 through the tissue held within the circumference ofthe stapled tissue.

In various embodiments, the adjusting shaft 90 is movably supportedwithin the handle assembly 60 that may comprise two handle casingsegments 61 that are interconnected together by suitable fastenerarrangements for ease of assembly. The trigger 120 is pivotally attachedto the handle assembly 60 by a pivot pin 121. A spring 122 is supportedon pivot pin 121 and serves to bias the trigger 120 away from the handleassembly 60 to an unactuated position. A safety yoke 123 is pivotallycoupled to the handle 60 by pin 124 such that it can be pivoted betweena safe position wherein the trigger 120 cannot be depressed towards thehandle 60 and an off position wherein the safety yoke 123 does notinhibit pivotal travel of the trigger assembly 120 toward the handleassembly 60. As can be seen in FIG. 5, the trigger 120 may have a pairof fins 125 that are sized to be received in slots 132 in a firing clip130 that is attached to the proximal end 133 of compression shaft 84 bya protrusion 134 or other suitable fastener arrangements. Sucharrangement permits the distal axial movement (arrow “DD”) and theproximal axial movement (arrow “PD”) of the compression shaft 84 bypivoting the trigger 120 as will be further discussed below.

As can be seen in FIGS. 5 and 6, the adjustment shaft 90 has a distalportion 141 that is attached to the top and bottom tension bands 86, 87and a proximal portion 142 that is adjoined to the distal portion 141 bya reduced diameter segment 143. The proximal portion 142 is axiallyreceived within an axial passage 152 in a distal closure nut 150 that iskeyed onto or otherwise attached to a proximal closure nut 160 to form aclosure nut assembly generally designated as 161 such that the distalclosure nut 150 and the proximal closure nut 160 may rotate together.The distal closure nut 150 may further have a distally extending hubportion 154 that abuts an inwardly extending retainer flange formedinside the handle assembly 60. Such arrangement permits the distalclosure nut 150 to freely rotate within the handle assembly 60, but isunable to move axially therewithin. Likewise, the proximal end portion142 of the adjustment shaft 90 is axially received within an axialpassage within the proximal closure nut 160. Also in variousembodiments, the closure knob assembly 40 is attached to the proximalend of the proximal closure nut 160 in the various manners described inU.S. Pat. No. 7,506,791, the disclosure of which has been hereinincorporated by reference. The closure knob assembly and adjustmentshaft and related components for adjusting the position of the anvilrelative to the stapling head is referred to herein as the “anviladjustment system”. Rotation of the closure knob assembly 40 results inthe axial travel of the anvil shaft 210 in the proximal and distaldirections depending on the direction in which the knob assembly 40 isrotated.

Turning to FIGS. 2-4, one implementation of an anvil assembly 200 isshown. As can be seen in those Figures, the anvil assembly 200 includesthe anvil shaft 210 that has a tissue-penetrating tip member 212 formedat the distal end thereof. In various embodiments, thetissue-penetrating tip member 212 includes a substantiallyconically-shaped tip portion 214 that terminates in a sharpened point216. In various embodiments, the tissue-penetrating tip member 212 maybe integrally formed with the anvil shaft 210. In variousimplementations, the anvil shaft 210 and tissue-penetrating tip member212 are fabricated from metal material.

Various forms of the anvil assembly 200 further include a plurality oflinkage assemblies 220. In the embodiment depicted in FIG. 4, fourlinkage assemblies 220 are employed. Each linkage assembly 220 includesa distal link 222 that is pivotally coupled to the tissue-penetratingtip member 212. Each distal link 222 is pivotally coupled to a primaryanvil plate segment 224 that is, intern, pivotally coupled to a collar230 that is movably supported on the anvil shaft 210. Each primary anvilplate segment 224 has a primary staple-forming surface 226 formedthereon. In addition, the anvil assembly 200 further includes aplurality of secondary anvil plate segments 227 that are pivotallycoupled to the collar 230. As can be seen in FIG. 4, for example, asecondary anvil plate segment 227 is arranged between adjacent primaryanvil plate segments 224. In various embodiments, the primary anvilplate segments 224 and the secondary anvil plate segments 227 havecomplementary-shaped surfaces thereon, such that when the primary anvilplate segments 224 are pivoted to the open position (FIG. 3), theycontact the adjacent secondary anvil plate segments 227 and pivot themto the open position as well to form a substantially planar anvil plateassembly 229. Each secondary anvil plate segment 227 has a primarystaple-forming surface 228 thereon that cooperates with the primarystaple-forming surfaces 226 of the primary anvil segments 224.

FIG. 2 illustrates the anvil assembly 200 in a collapsed orientationthat permits the anvil assembly 200 to be inserted through a trocarcannula or other opening in the body. As the surgeon draws the anvilshaft 210 in the proximal direction “PD” by rotating the knob 40, thecollar 230 will eventually contact the distal end 102 of the central hubportion 100 of the compression shaft 85. Continued movement of the anvilshaft 210 in the proximal direction will cause the movable collar 230 totravel distally on the anvil shaft 210 until it contacts a distal flange232 on the anvil shaft 210. See FIG. 3. When in that position, the anvilassembly 200 is in the “expanded” or deployed orientation and theprimary and secondary staple-forming surfaces 226, 228 of the primaryand secondary anvil plate segments 224, 227 form the substantiallyplanar anvil plate assembly 229 whose staple-forming surface is inconfronting relationship to the staple cartridge 26 in the stapling head20. The surgeon may then activate or “fire” the circular stapler 10 todrive the staples 28 into the staple-forming surfaces 226, 228.

The circular stapling instrument 10 may be employed to perform a varietyof different surgical procedures. FIG. 8 illustrates use of the circularstapling instrument 10 in connection with performing a Roux-en-Yprocedure. When performing Roux-en-Y gastric bypass surgerylaparoscopically, a number of conventional trocar devices 250 are placedin various locations through the patient's abdominal wall to providepassages through which surgical instruments, grasping devices and/orcameras may be inserted. As indicated above, such procedure involves thecreation of a small stomach pouch 260 and the attachment of the jejunum262 thereto by means of an anastomosis 264 (commonly referred to as theG-J anastomosis). The stomach pouch 260 may be formed by inserting aconventional endocutter (not shown) through the appropriate trocardevice 250 and cutting and stapling a portion 268 of the stomach 266 atthe esophago-gastric junction. A conventional endocutter may also beused to sever the jejunum 262 at a location 263 beyond where it exitsthe stomach 266. The severed end 265 of the jejunum 262 is then attachedto the stomach pouch 260 using the anvil assembly 200 attached to acircular stapling instrument 10 that has been inserted through thetrocar device 250.

In particular, the circular stapling head 20 with the anvil assembly 200coupled thereto in a collapsed orientation (FIG. 2) is inserted throughthe cannula portion 252 of the trocar device 250. The anvil assembly 200is advanced through the severed end portion 265 of the jejunum 262 bypushing the tissue-penetrating tip member 212 therethrough and alsothrough the wall of the stomach pouch 260. Once the anvil assembly 200has been inserted through the wall of the stomach pouch 260, the surgeonmay then draw the anvil assembly 200 toward the stapling head 20 of thecircular stapling instrument 10 to capture the wall (“T”) of the pouch260 and the wall (“T1”) of the severed end portion 265 of the jejunum262 between the anvil assembly 200 and the stapling head 20. As theanvil assembly 200 is drawn into expanding contact with the distal end102 of the central hub portion 100 of the compression shaft 85, theanvil plate assembly 229 is formed. The stapling device 100 may then befired to create the G-J anastomosis. The circular stapling instrument 10may then be withdrawn from the trocar device 250.

A second circular stapling instrument 10 or the prior circular staplinginstrument 10 with a new staple cartridge 26 installed therein may thenbe inserted through the cannula portion 252 of an appropriately locatedtrocar device 250 and the tissue penetrating tip member 212 may be usedto penetrate through a portion 267 of the jejunum below the duodenum 269and through a portion of the lower jejunum portion 270 as shown in FIG.8. Once the anvil assembly 200 has been located within the lower jejunumportion 270, the surgeon may then draw the anvil assembly 200 toward thestapling head 20 which causes the anvil assembly 200 to move to theexpanded or deployed orientation. The surgeon continues to draw theexpanded anvil plate assembly 200 toward the stapling head assembly 20to capture the walls “(T2” and “T3”) of the jejunum portions 267, 270therebetween and then fires the circular stapling instrument 10 to formanastomosis 272 therebetween (commonly referred to as the J-Janastomosis). Such arrangement therefore bypasses the severed portion ofstomach 266 and duodenum 269.

FIGS. 9-11 illustrate another circular stapling instrument 310 of thepresent invention. Various embodiments of the circular staplinginstrument 310 have components that are substantially identical to thecircular stapling instrument 10 described above and have been identifiedwith the same element numbers in FIGS. 9-11. Those components thatdiffer from or are in addition to the components of the circularstapling instrument 10 will now be described. As can be seen in FIG. 9,the circular stapling instrument 310 includes an anvil assembly 320 thatincludes an anvil shaft 321. The anvil shaft 321 is attached to the toptension band 86 and bottom tension band 87 on the circular staplinginstrument 310 by fasteners 89. The proximal ends of the top tensionband 86 and bottom tension band 87 may be attached to a distal end ofthe adjustment shaft 90 as was described above. In this embodiment, thedistal compression shaft portion 85 is configured to engage the stapledriver assembly 24 that is operably supported within the stapling head20. Thus, axial movement of the compression shaft 84 within the outertubular shroud 82 causes the staple driver assembly 24 to move axiallywithin the casing member 22 of the stapling head 20. As was discussedabove, actuation of the firing trigger 120 (FIG. 1) will cause thecompression shaft 84 to move in the distal direction (arrow “DD”)thereby driving the staple driver assembly 24 distally to fire thestaples in the staple cartridge 26 into forming contact with the anvilassembly 320. As the staple driver assembly 24 is driven distally, italso drives the distal end of the knife 30 through the tissue heldwithin the circumference of the stapled tissue.

Turning to FIGS. 10 and 11, one implementation of an anvil assembly 320is shown. As can be seen in those Figures, a tissue-penetrating tipmember 322 is formed at the distal end of the anvil shaft 321. Invarious embodiments, the tissue-penetrating tip member 322 includes asubstantially conically-shaped tip portion 324 that terminates in asharpened point 326. In various embodiments, the tissue-penetrating tipmember 322 may be integrally formed with the anvil shaft 321. The anvilshaft 321 and tissue-penetrating tip member 324 is fabricated from metalmaterial.

Various forms of the anvil assembly 320 further include an anvil linkageassembly 330. In the embodiment depicted in FIGS. 10 and 11, the anvillinkage assembly 330 includes a plurality of (four) outer anvil platesegments 332 that are pivotally coupled to the tissue-penetrating tipmember 324 by corresponding first links 334. Each outer anvil platesegment 332 has a staple-forming surface 336 that has staple-formingpockets 338 formed therein. When the anvil assembly 320 is in theexpanded or deployed position (FIG. 11), the staple-forming pockets 338correspond to the outermost row of staples within the staple cartridge26 supported in the stapling head 20 of the circular stapling instrument310.

As can also be seen in FIGS. 10 and 11, the anvil linkage assembly 330further comprises a collection of inner anvil plate segments 340. Theinner anvil plate segments 340 are pivotally coupled to an inner linkageassembly 350 that is coupled to the anvil shaft 321. In at least oneimplementation, for example, the inner linkage assembly 350 includes acentral collar 352 that is attached to the anvil shaft 321. Each inneranvil plate segment 340 is pivotally coupled to the central collar 352by a primary link 354. The inner linkage assembly 350 further includes aplurality of actuator blocks 356. Each inner anvil plate segment 340 hasa corresponding actuator block 356 attached thereto by a secondary link358. Each inner anvil plate segment 340 has a staple-forming surface 342that has staple-forming pockets 344 therein. When the anvil assembly 320is in the expanded or deployed position (FIG. 11), the staple-formingpockets 344 correspond to the innermost row of staples within the staplecartridge 36 in the circular stapling instrument 310.

In various embodiments, a central hub portion 360 extends centrallythrough the stapling head 20. A proximal end 361 of the central hubportion 360 is configured to slidably engage the inside wall of thetubular shroud 82 as can be seen in FIG. 11. The compression shaft 84 isfree to move axially relative to the central hub portion 360 to drivethe staple driver assembly 24 distally. Thus, axial movement of thecompression shaft 84 within the tubular shroud 82 causes the stapledriver assembly 24 to move axially within the casing member 22 of thestapling head 20. As will be discussed below, actuation of the firingtrigger 120 will cause the compression shaft 84 to move in the distaldirection (arrow “DD”) thereby driving the staple driver assembly 24distally to fire the staples in the staple cartridge 26 into formingcontact with the substantially planar anvil plate assembly 346 formed bythe outer anvil plate segments332 and the inner anvil plate segments340. As the staple driver assembly 24 is driven distally, it also drivesthe distal end of the knife 30 through the tissue held within thecircumference of the stapled tissue.

In various implementations, the central hub portion 360 is alsoconfigured to move axially within the stapling head 20. As can be seenin FIGS. 9 and 11, an actuator rod 363 is coupled to the proximal end364 of the central hub portion 360 and is coupled to a slider switch 365mounted in the handle 60. The slider switch 365 may be configured toslide distally and proximally to axially advance and retract the centralhub portion 360. The slider switch may be configured with a series ofdetents (not shown) or other structures (nor shown) which define switchpositions that correspond to axial positions for the central hub portion360. Thus, the slider switch 365 and ultimately the central hub portion360 will be locked in position and unable to move axially when theslider switch 365 is moved to one of those switch positions.

FIG. 10 illustrates the anvil assembly 320 in a collapsed orientationthat permits the anvil assembly 320 to be inserted through a cannulaportion of a trocar device or other opening in the body. Once the anvilassembly 320 has been punctured through the tissue to be cut andstapled, the surgeon draws the anvil shaft 321 in the proximal direction“PD” by rotating the knob 40. Once the collapsed anvil assembly 320 isdrawn adjacent to the staple cartridge 26, the surgeon may then advancethe central hub portion 360 distally to cause the anvil assembly 320 tomove to the expanded or deployed orientation. As the distal end 362 ofthe central hub portion 360 moves distally, it contacts the actuatorblocks 356 of the inner linkage assembly 350. Movement of the actuatorblocks 356 distally facilitates pivotal movement of the inner anvilplate segments 340 into contact with the outer anvil plate segments 332to bias the outer anvil plate segments 332 radially outward to form asubstantially planar anvil plate assembly 346 as shown in FIG. 11. Whenin that position, the anvil assembly 320 is in the “expanded” ordeployed orientation and the staple-forming surfaces 336, 342 of theanvil plate segments 332, 340 are in confronting relationship with thestaple cartridge 26 in the stapling head 20 of the circular staplinginstrument 310. The surgeon may then activate or “fire” the circularstapling instrument 310 to drive the staples into the staple-formingpockets 338, 344 in the staple-forming surfaces 336, 342, respectively.The circular stapling instrument 310 may, for example, be used toperform a Roux-en-Y procedure in the manner described above, as well asto perform other surgical procedures.

FIGS. 12-15 illustrate another expandable anvil embodiment of variousforms of the present invention that may be used in connection with acircular stapling instrument 410. Various embodiments of the circularstapling instrument 410 have components that are substantially identicalto the circular stapling instrument 10 described above and therefore,their construction and operation will not be repeated again, beyond thatwhich is necessary to understand the construction and operation of thecircular stapling instrument 410. As can be seen in FIGS. 12-15, thecircular stapling instrument 410 includes an expandable and collapsibleanvil assembly 420. In this implementation, the circular staplinginstrument 420 includes a trocar shaft 412 that may be attached to thetop tension band 86 and bottom tension band 87 of the circular staplinginstrument 410 by fasteners 89. The proximal ends of the top tensionband 86 and bottom tension band 87 may be attached to a distal end of anadjustment shaft 90 as was described above.

FIGS. 13 and 14 illustrate one form of trocar shaft 412 that may beemployed with various embodiments of the present invention. Those ofordinary skill in the art will also appreciate that various embodimentsof the present invention may also be employed with conventional trocarshaft arrangements without departing from the spirit and scope of thepresent invention. As can be seen in FIGS. 13 and 14, the trocar shaft412 is provided with a plurality of (preferably four) outwardlyextending attachment fins 414. Such arrangement permits the trocar shaft412 to be non-rotatably attached to a variety of different tipassemblies that may be employed in connection with different types ofend effector arrangements that are specifically configured to performvarious surgical procedures and actions.

The circular stapling instrument 410 may be effectively employed with ananvil assembly 420 which serves to form the staples as they are drivenfrom the staple cartridge 26. As can be seen in FIG. 14, one form ofanvil assembly 420 includes a tissue-penetrating tip member 430 that isattachable to the trocar shaft 412. In various embodiments, thetissue-penetrating tip member 430 includes a substantiallyconically-shaped tip portion 432 that terminates in a sharpened point434 and has an anvil shaft 436 attached thereto. The proximal end 438 ofthe anvil shaft 436 is substantially hollow and sized to receive thetrocar tip 416 therein. The proximal end 438 has a pair of spacedattachment tabs 440 protruding therefrom which extend between the trocarfins 414. Each attachment tab 440 has a hole or recess 442 therein thatis oriented to receive a corresponding detent 418 formed on the trocarshaft 412. Thus, when the detents 418 snap into their corresponding holeor recess 442, the tissue-penetrating tip member 430 is affixed to thetrocar shaft 412 for travel therewith. In various embodiments, thetissue-penetrating tip member 430 is fabricated from metal material.

Various forms of the anvil assembly 420 further include a plurality ofanvil plates 450. In the embodiment depicted in FIGS. 12-15, two anvilplates 450 are employed. In at least one embodiment, each anvil plate450 has an arcuate shape and has at least one staple-forming pockettherein. In a preferred embodiment, each anvil plate 450 has a firstarcuate configuration 452 of staple-forming pockets 454 therein and asecond arcuate configuration 456 of staple-forming pockets 458 thereinthat, when the anvil assembly 420 is in the expanded or deployedorientation, correspond to the circular array of staples within thestaple cartridge 26. In various embodiments, the anvil plates 450 eachhave an anvil hub portion 460 that extends around a portion of the anvilshaft 436. The anvil plates 450 are movably coupled together by at leasttwo spring clips 462 (shown in FIG. 15). The spring clips 462 serve tobias the anvil hub portions 460 into frictional engagement with theanvil shaft 436 to retain the anvil plates 450 in the collapsedorientation. See FIGS. 12 and 13. In addition, in at least oneimplementation, each anvil plate 450 has a tapered inner wall portion464 formed thereon. When the anvil plates 450 are in collapsedorientation, a space 466 is provided between the tapered inner wallportions 464 of the confronting anvil plates 450. See FIG. 13.

Various embodiments of the anvil assembly 420 further comprise an anvilexpansion member 470 that has a centrally-disposed conical tip portion472 that is sized to axially extend into the opening 466 when the anvilassembly 420 is moved in the proximal direction “PD” toward the staplinghead 20. A hollow expansion shaft 474 extends from the conical tipportion 472 and is sized to permit the anvil shaft 436 to axially movewithin it. In addition, the anvil expansion member 470 further has apair of diametrically-opposed anvil plate sections 476 protrudingtherefrom. The anvil plate sections 476 are sized and shaped relative tothe anvil plates 450 such that when they are received between theconfronting anvil plates 450, they interlock therewith to form asubstantially planar and annular anvil plate assembly 480. See FIG. 15.

As can be seen in FIGS. 12 and 13, each of the anvil plate sections 476has a first arcuate configuration 452 of staple-forming pockets 454therein and a second arcuate configuration 456 of staple-forming pockets458 therein that, when the anvil assembly 420 is in expanded or deployedorientation, correspond to the circular array of staples within thestaple cartridge 26. It will be understood, that the staple-formingpockets 454, 458 serve to form the staples as they are driven throughthe tissue “T” to be stapled and into the anvil plate assembly 480.

In various embodiments, the expansion shaft 474 extends through acentrally-disposed hub shaft (not shown) in the stapling head 20. Theexpansion shaft 474 is sized and shaped relative to the hub shaft toestablish a slidable frictional fit therewith. FIGS. 12 and 13illustrate a starting position of the anvil expansion member 470 whenthe anvil assembly 420 is in the collapsed position. When in thatposition, the anvil expansion member 470 is retained in that position bythe frictional fit established between the expansion shaft 474 and thehub shaft. When in the collapsed orientation, the surgeon may then forcethe tissue-penetrating tip member 432 through the tissue “T” to bestapled to enable the anvil assembly 420 to extend therethrough. Oncethe collapsed anvil assembly 420 is located on the opposite side of thetissue “T”, the substantially planar anvil plate assembly 480 is thendrawn toward the stapling head 20 to capture the target tissuestherebetween. The anvil assembly 420 is moved in the proximal direction“PD” by rotating the knob 40 on the handle portion 60 to drawn thetrocar shaft 412 toward the handle 60 as is known. As the anvil assembly420 is moved in the proximal direction, the tip portion 472 of the anvilexpansion member 470 enters the opening 466 between the anvil plates 450and engages the tapered inner walls 464 of the anvil plates 450 to biasthe anvil plates 450 radially outward in the radial direction “RD” (FIG.14) until the anvil plate sections 476 are received between the anvilplates 450. See FIG. 15. When in that expanded orientation, the anvilplates 450 interlock with the anvil plate sections 476 to form asubstantially planar and annular anvil plate assembly 480. Furthermovement of the anvil assembly 420 in the proximal direction “PD”,causes the anvil expansion shaft 474 to slide within the hub shaft toenable the anvil assembly 420 to be moved to the desired position forstapling and cutting tissue. Once the anvil assembly 420 has beenproperly positioned relative to the stapling head 20, the surgeon maythen “fire” the device by activating the firing trigger 60 which drivesthe knife 30 and drives the staples into forming contact with thesubstantially planar annular anvil plate assembly 480. The expandableanvil assembly 420 may be in connection with a circular staplinginstruments of the type described above or other circular staplinginstruments may, for example, to be used to perform a Roux-en-Yprocedure in the manner described above, as well as to perform othersurgical procedures.

FIGS. 16-19 illustrate another expandable anvil assembly 520 that may beemployed with the circular stapling instrument 510 to perform variousstapling procedures such as the Roux-en-Y procedure described above.Various embodiments of the circular stapling instrument 510 havecomponents that are substantially identical to the circular staplinginstruments 310 described above and/or others described and therefore,their construction and operation will not be repeated again beyond thatwhich is necessary to understand the construction and operation of thecircular stapling instrument 510.

In at least one implementation, the expandable anvil assembly 520comprises an umbrella-like assembly that includes a plurality ofselectively splayable first anvil links 530 that have a distal endportion 532 that is pivotally attached to an anvil shaft 540. Each firstanvil link has an elongated body portion 534 and a proximal end 536 thathas a first anvil plate segment 538 formed on thereon. The first anvillinks 530 may be fabricated from metal material. The first anvil platesegments 538 each have a first staple-forming surface that has a firstarcuate configuration of first staple-forming pockets 539 therein. SeeFIG. 18. In various embodiments, each of the first anvil links 530 has alock ring detent 535 formed thereon and are movably received within alock ring 550.

In various embodiments, the expandable anvil assembly 520 furtherincludes a second anvil link assembly 570 that includes a plurality ofprimary links 572 that are pivotally coupled to an intermediate harnessring 574. A secondary anvil plate segment 576 is pivotally coupled toeach of the primary links 572. The secondary anvil plate segments 576are pivotally coupled to an actuator ring 580. The intermediate harnessring 574 and the actuator ring 580 are movably journaled on the anvilshaft 540. Each of the secondary anvil plate segments 576 have astaple-forming underside 577 thereon that have a staple-forming pockets579 therein. See FIG. 18.

This embodiment further includes a centrally disposed actuator hub 590that is movably supported within the stapling head 20 as shown in FIG.19. The proximal end 592 of the actuator hub 590 is attached to theactuator rod 361 which is coupled to the slider switch 365 on the handle60. Movement of the slider switch 365 in the distal direction “DD” willdrive the actuator hub 590 in the distal direction within the staplinghead 20. Such movement of the actuator hub 590 drives the second anvillink assembly 570 distally to cause the first anvil links 530 to splayopen. As the first anvil links 530 splay open, the locking ring 550 iscaused to slide up the first anvil links 530. The surgeon will continueto advance the second anvil link assembly 570 distally until thestaple-forming surfaces 577 of the secondary anvil plate segments 576are in confronting relationship to the staple cartridge 26 in thestapling head 20. FIG. 16 illustrates the secondary anvil plate segments576 in an intermediate position prior to attaining the confrontingrelationship relative to the staple cartridge 26. In variousembodiments, the slider switch 365 may be configured with detents orother locking arrangements to define the final “firing” position of thesecond anvil link assembly wherein the first anvil plate segments andthe secondary anvil plate segments cooperate to form a substantiallyplanar annular anvil plate assembly generally designated as 595. SeeFIG. 18. Thus, when the slider switch 365 is locked in position, theactuator hub 590 is locked in position wherein the intermediate harnessring 574 is in abutting relationship with a locking flange 541 on theanvil shaft 540. When in that position, the locking ring 550 is inabutting relationship with the locking ring detents 535 on the firstanvil links 530 to lock the first anvil links 530 in that splayedposition.

In various implementations, the anvil shaft 540 of the circular staplinginstrument 510 has a trocar tip portion 542 that terminates in a pointedtissue-penetrating tip 544. See FIG. 17. In FIG. 17, the expandableanvil assembly 520 is in the collapsed orientation. When in thecollapsed orientation, the trocar tip portion 542 may be used topuncture through tissue. As can be see in that Figure, for example, thetrocar tip portion 542 has punctured through the tissues “T” and “T1”that are to be cut and stapled. Thereafter, the surgeon may activate theslider switch 365 to form the substantially planar annular anvil plateassembly 595. Once the anvil plate assembly 595 has been formed inconfronting relationship with the staple cartridge 26 supported in thestapling head 20, the surgeon may activate the firing trigger 120 on thehandle 60 to fire the staples and knife 30 as described above.

In the past, laparoscopic colectomies were cumbersome to perform due tothe number of steps required to be performed to introduce the staplinginstruments to the surgical site. Problems with crossing staple lines,seeding from subject tissue removal, creation of ports for introductionof anvils into the body cavity, and colon defects from anvil placementwere often encountered when employing such procedures. The variousembodiments of the present invention described above may be effectivelyused to perform a laparoscopic colectomy while avoiding many, if not allof such problems.

FIGS. 20 and 21 illustrate a section of colon 600 that has a diseasedportion 602 that is to be removed therefrom. As can be seen in FIG. 21,a circular stapling instrument 10 of the type and constructionsdescribed above with a corresponding anvil assembly 420 of the type andconstruction described above is inserted into the colon 600 through therectum 604. The anvil assembly 420 is used to puncture through theportions of the colon wall “T” and “T1” when the anvil assembly 420 isin the collapsed position in the manners described above. FIG. 21illustrates this process generally. As can be seen in that Figure,conventional graspers 610 may be employed through appropriately locatedtrocars (not shown) to grasp the diseased portion 602. Those of ordinaryskill in the art will understand that any of the above-describedembodiments may be employed to perform this procedure. FIG. 22illustrates anvil assembly 520 as well as a pointed anvil assembly 620that has an auger-type tip formed thereon to penetrate the colon wall.Once the anvil assembly has penetrated through the colon wall portions“T” and “T1” the circular stapling instrument 10 may be operated asdescribed above to complete the anastomosis 606. Thereafter, theinstrument 10 is withdrawn out through the rectum 604.

FIG. 23 illustrates use of conventional endocutter devices 640 to severthe diseased colon portion 602. Again the endocutter 640 may be insertedthrough an appropriately located trocar. FIG. 24 illustrates removal ofthe diseased portion by inserting a conventional specimen retrievaldevice 650 through the colon 600 to grab the specimen 602 and eitherwithdraw it back out through the rectum 604 or to place it in a specimenretrieval bag 660 inserted through another appropriately placed trocar.

As can be appreciated from the foregoing, the various circular staplinginstrument configurations and anvil assembly configurations describedherein represent vast improvements over prior circular staplerarrangements. Use of the various circular stapling instrument and anvilembodiments of the present invention may eliminate the oftentime-consuming process of tying purse string sutures around the anvilshaft. In addition, the various anvil assemblies disclosed above may beeffectively used with conventional circular stapling instruments. Suchself-puncturing and self centering anvil arrangements may also eliminatethe need for creating “side-to-side” anastomosis. Various anvil assemblyembodiments of the present invention described above may also result ina reduction of the insertion and removal forces needed to use theinstruments. The need for creating another defect to insert an anvil inthe patient may also be eliminated when employing various embodiments ofthe present invention. Such embodiments of the present invention mayalso result in little or no dilation of the staple line which can leadto better hemostasis.

FIGS. 25-28 illustrate another expandable anvil assembly 700 that may beemployed with the circular stapling instrument 10 to perform variousstapling procedures such as the Roux-en-Y procedure described above. Inat least one implementation, the expandable anvil assembly 700 includesan anvil plate assembly 710 that, in at least one embodiment, includes aflexible ring member 712 that supports a plurality of metal anvil platesegments 720 thereon. The flexible ring member 712 may be fabricatedfrom an elastomeric material that permits the ring member 712 to becollapsed into a first configuration which permits it to be insertedthrough the cannula portion 181 of a trocar device 180 (FIG. 26) andthen spring open to a second configuration comprising a substantiallyplanar annular anvil plate assembly 710 as shown in FIGS. 27 and 28. Themetal anvil plate segments 720 are arcuate in shape and may be embeddedin or otherwise attached to the flexible ring member 712. Each anvilplate segment 720 has a staple-forming surface 722 thereon that has aplurality of arcuate configurations of staple-forming pockets 726therein. In one embodiment for example, the staple-forming surface 722has an inner configuration 724 and an outer configuration 725 ofstaple-forming pockets 726 therein. As can be seen in FIGS. 25-27, theinner configuration 724 of staple-forming pockets 726 is staggered withrespect to the outer configuration 725 of staple-forming pockets 726 tomatch the concentric array of staples in the stapling head 20.

In various embodiments, the expandable anvil assembly 700 furtherincludes an anvil support member 730 that is configured for attachmentto the anvil plate assembly 710 to orient and provide load bearingsupport thereto. As can be seen in FIGS. 25 and 29-31, in at least oneimplementation, the anvil support member 730 comprises a central shaft732 that has a proximal end 734 that is configured to be attached to theend of the trocar shaft of the circular stapling device. The proximalend 734 may have a cavity therein sized to receive the trocar tiptherein. In other embodiments, the proximal end 734 is configured toreleasably engage a trocar shaft arrangement of the type disclosed inFIG. 14.

In at least one implementation, the anvil support member 730 includes alinkage assembly 740 that is movably journaled on the central shaft 732such that it is movable thereon between a collapsed orientation (FIG.29) and an expanded or deployed orientation (FIGS. 25 30). As can beseen in FIGS. 25, 29, and 30, the linkage assembly 740 comprises aplurality of jointed links 742 that each include a distal link 744 and aproximal link 746 that are pivotally (pinned) together. In otherembodiments, however, each distal link 744 may be coupled to acorresponding proximal link 746 by a living hinge arrangement thatincludes a detent arrangement to lock the links together when in theanvil plate supporting position. Each of the distal links 744 ispivotally coupled to a distal end ring 750 that is mounted to the distalend of the central shaft 732. Each of the proximal links 746 ispivotally coupled to a lock ring 752 that is movably journaled on thecentral shaft 732. A retention collar 760, in the form of a plurality ofspaced outwardly extending flanges 762, is provided on the central shaft732 to retainingly engage the lock ring 752 when the linkage assembly740 is in the expanded or deployed orientation as shown in FIG. 30. Whenthe lock ring 752 is retainingly engaged with the retention collar 760,the linkage assembly 740 is locked in the expanded orientation.

As can be seen in FIGS. 29-31, each of the proximal links 746 has alatch feature 748 formed thereon. The latch feature 748 is adapted toengage a corresponding latch tab 728 formed on the underside 727 of eachanvil plate 720. As can be seen in FIG. 28 in at least one embodiment,each anvil plate 720 has two latch tabs 728 thereon. The latch tabs 728are positioned such that when they latchingly engage the correspondinglatch features 748 on the anvil support member 730, the staple-formingpockets 726 in the anvil plates 720 are aligned with correspondingstaples in the stapling head of the circular stapling instrument, suchthat when the staples are driven into the anvil plates 720, the staplesare properly formed by the corresponding staple-forming pockets 726therein. In alternative embodiments, the ends of the links may beconfigured to retainingly engage corresponding holes in the anvil plates720.

In use, the anvil plate assembly 710 is oriented in the collapsedorientation so that it can be passed through the cannula portion 181 ofthe trocar device 180 (FIG. 26) or other opening in the body (e.g.,through the colon, etc.). The anvil support member 730 is likewiseoriented in the collapsed orientation (FIG. 29) so that it may also passthrough the cannula portion 181 or other body opening. It may beattached to the trocar shaft of the circular stapling instrument andinserted through the cannula portion 181 or body opening with thestapling head of the instrument. In other approaches, however, thecollapsed anvil support member 730 may be separately inserted into thepatient and then attached to the trocar shaft of the circular staplinginstrument that has been inserted, for example, through a cannulaportion of another trocar device or other opening. Once the anvil plateassembly 730 has passed through the cannula portion 181, the flexiblering 712 causes the plate assembly to flex into its planar orientation.If the anvil support member 730 was inserted through the cannula portionor opening without being attached to the trocar shaft of the circularstapling instrument, with, for example, a grasping device, the surgeonmay use the grasping device to move the linkage assembly 740 to theexpanded orientation such that the lock ring 752 is brought into lockingengagement with the retention collar 760. Thereafter, the expanded anvilsupport member 730 is mated to the anvil plate assembly 710. Morespecifically, the anvil plate assembly 710 is oriented relative to theproximal links 746 of the linkage assembly 740 such that the latchfeatures 748 are first oriented adjacent to the corresponding latch tabs728 on the anvil plates 720 and then rotated into latching engagementtherewith as illustrated in FIG. 31. The assembled anvil assembly 700may then be attached to the trocar shaft of the circular staplinginstrument. To ensure that the staple-forming pockets 726 areinsubstantial registry with the corresponding staples in the staplinghead, the proximal end 734 of the shaft 732 is attached to the trocarshaft in an aligned manner. Such alignment may be accomplished by usingthe trocar shaft arrangement configured as shown in FIG. 14 or othersuitable alignment arrangement (i.e., keys/keyways, grooves, etc.). Inapplications wherein the anvil assembly 700 is introduced into thepatient while it is attached to the trocar shaft of the circularstapling instrument, the surgeon may insert the anvil plate assembly 710over the collapsed anvil support member 730. Once the anvil plateassembly 710 has been inserted over the collapsed anvil support member730, the surgeon may then move the anvil support member 730 to theexpanded orientation and then the anvil plate assembly 710 may then beattached thereto in the manner discussed above.

FIGS. 32-38 illustrate another anvil plate assembly 810 that can beinserted through a cannula portion 181 of a trocar device 180 or otheropening in the body in a collapsed orientation (FIG. 26) and then openedto assume a substantially planar orientation or configuration (FIG. 38).In at least one implementation, the anvil plate assembly 810 includes aplurality of anvil plates 820 that are movably fastened together by aplurality of first and second spring clips 840, 860. Each anvil plate820 has an arcuate shape such that when configured in the expandedorientation, the anvil plates 820 cooperate to form a substantiallyannular and planar anvil plate configuration as shown in FIG. 38.

In various embodiments, the ends of the anvil plates 820 are configuredto interlock together to form the expanded anvil plate assembly shown inFIG. 38. When assembled together, the anvil plate assembly 810 includesa pair of first attachment joints 821 that are opposed to each other anda pair of second attachment joints 850 that are opposed to each other.See FIGS. 32 and 38. FIGS. 33 and 34 illustrate an exemplary firstattachment joint 821. As can be seen in those Figures, the adjacentfirst ends 822 of the anvil plates 820 forming a first attachment joint821 each have a first notch 823 therein. Each first end 822 further hasa planar first attachment tab 824 protruding therefrom that is sized toslidably extend into a complementary-shaped first slot 825 formed in thefirst end 822 of the adjoining anvil plate 820. The first ends 822 aremovably coupled together by a first spring clip 840. The ends 842 ofeach first spring clip 840 are movably retained within first springslots 843 formed in the first ends 822. When the anvil plate assembly810 is in the collapsed orientation, the first spring clips 840 retainthe first ends together as shown in FIGS. 32 and 33. When the anvilplate assembly 810 is in the expanded orientation, the ends 842 of thefirst spring clips 840 slide in their respective first spring slots 843to retain the first ends 822 of the anvil plates 820 in interlockedengagement as shown in FIGS. 34 and 38.

FIGS. 35-37 illustrate a second attachment joint 850. As can be seen inthose Figures, the adjacent second ends 852 of the attachment plates 820forming a second attachment joint 850 each have a second notch 853therein. Each second end 852 further has a planar second attachment tab854 protruding therefrom that is sized to extend into acomplementary-shaped second slot 855 formed in the second end 852 of theadjoining anvil plate 820. The second ends 852 are movably coupledtogether by a second spring clip 860. The ends 862 of each second springclip 860 are movably retained within second spring slots 863 formed inthe second ends 852. When the anvil plate assembly 810 is in thecollapsed orientation, the second spring clips 860 retain the secondends 852 together as shown in FIGS. 32 and 35. When the anvil plateassembly 810 is in the expanded orientation, the ends 862 of the secondspring clips 860 slide in their respective second spring slots 863 toretain the second ends 852 of the anvil plates 820 in interlockedengagement as shown in FIGS. 36 and 38. In various embodiments, theattachment tabs 824, 854 are substantially parallel with thestaple-forming surfaces on the anvil plates 820 such that when the anvilplates 820 are assembled together in the expanded orientation, theattachment tabs 824, 854 provide additional support and rigidity to theanvil plate assembly 810 in the plane that is substantiallyperpendicular to the direction in which the staples are being fired.

Each anvil plate segment 820 has a staple-forming surface 870 thereonthat has a plurality of arcuate configurations of staple-forming pockets876 therein. In one embodiment for example, the staple-forming surface870 has an inner configuration 872 and an outer configuration 874 ofstaple-forming pockets 876 therein. When in the expanded orientation,the anvil plate assembly 810 may be attached to the anvil support member730 and used in the manner described above. In particular, each of theanvil plates 820 may have two latch tabs (not shown) formed on theunderside thereof. The latch tabs are positioned such that when theylatchingly engage the corresponding latch features 748 on the anvilsupport member 730, the staple-forming pockets 876 in the anvil plates820 are aligned with corresponding staples in the stapling head of thecircular stapling device, such that when the staples are driven into theanvil plates 820, the staples are properly formed by the correspondingstaple-forming pockets 876. As shown in FIG. 32, a tether 880 may beemployed to retain the anvil assembly 810 in the collapsed orientationduring insertion into the patient. Thereafter, the tether 880 may be cutusing a conventional cutting device 890 to permit the anvil assembly 810to be moved to the expanded orientation.

FIGS. 39A-39F, 39AA, 39CC, 40, 40A, and 41 illustrate another expandableanvil plate assembly 900 of the present invention. In oneimplementation, the anvil plate assembly 900 includes four arcuate anvilplate segments 910 that are coupled together by hinges 912, 912′, 912″.FIGS. 39A, 39B, and 39AA illustrate the anvil plate assembly 900 in acompletely collapsed configuration. In the illustrated embodiment, theanvil plate assembly 900, when in the completely collapsedconfiguration, is sized to fit through the cannula portion 181 of atrocar device 180 that has a 12 mm opening. See FIG. 41. As can be seenin that Figure, the hinges 912 are partially separatable to enable theplate assembly 900 to assume that position. Once the anvil assembly 900has been inserted through the trocar cannula 181 or other body opening,the anvil assembly 900 is unfolded as illustrated in FIGS. 39C-39F and39CC to form a substantially planar anvil plate assembly 900. Each ofthe anvil plate segments 910, which may be fabricated from metalmaterial, has a staple-forming surface 914 that has an innerconfiguration 916 of staple-forming pockets 918 and an outerconfiguration 920 of staple-forming pockets 918 therein.

FIG. 42 illustrates another expandable anvil plate assembly 930 of thepresent invention. In one implementation, the anvil plate assembly 930includes four arcuate anvil plate segments 932 that are coupled togetherby hinges 934. In the illustrated embodiment, a tether 940 is threadedthrough each of the segments 932. The collapsed anvil assembly 930 maybe pulled through the trocar cannula 181 by a conventional graspinginstrument 950 that has been inserted through another trocar device (notshown). As the collapsed anvil assembly 930 is inserted through thecannula 181, the end 942 of the tether is threaded out through thecannula 181 where it can be accessed outside of the trocar device 180.Once the collapsed anvil plate assembly 930 has been inserted throughthe cannula portion 181, the surgeon may then pull the end 942 of thetether 940 to draw the two end anvil plate segments 932 together to formthe substantially planar annular anvil plate assembly. A releasablelatch feature (not shown) is provided on each of the end segments tolock the anvil assembly 930 in the expanded configuration. As can beseen in FIG. 42, each of anvil plate segments 932, which may befabricated from metal material, has a staple-forming surface 936 thathas an inner configuration 937 of staple-forming pockets 938 and anouter configuration 939 of staple-forming pockets 938 therein.

While the anvil plate assemblies 900, 930 may be employed with any ofthe anvil support member arrangements disclosed herein, FIG. 43illustrates another anvil support member arrangement 950 of the presentinvention. One implementation of the anvil support member arrangement950 includes an anvil bearing plate assembly 960 that is journaled on ananvil shaft 970. The anvil assembly 900, 930 (whichever the case may be)is inserted through the cannula portion 181. The anvil shaft 970 is alsosized to be inserted through the cannula portion 181 or other bodyopening. The bearing plate assembly 960 may, for example, comprise twobearing plate halves 961 a, 961 b that are hingably coupled together.Such arrangement permits the bearing plate assembly 960 to be folded toa collapsed position wherein it may be inserted through the cannulaportion 181 or other body opening. Once all three components 900 or 930,960, 970 have been inserted into the patient, they may be assembled asshown in FIGS. 43 and 43A-43C. The bearing plate assembly 960 may bekeyed onto the anvil shaft 970 to orient the bearing plate 960 in adesired orientation thereon. The anvil shaft 970 is configured to beattached to the trocar tip of the surgical stapling instrument in adesired orientation. The anvil shaft 970 may, for example, be configuredas shown in FIG. 14. The bearing plate assembly 960 may also beconfigured to latch in position with the anvil shaft 970 or latch withthe end cap 972 of the anvil shaft. As can also be seen in FIG. 43, inthe illustrated embodiment, the underside 962 of the bearing plateassembly 960 is configured to latch with the particular anvil plateassembly 900, 930. In the depicted embodiment, a notch 964 is providedto receive the hinge 912′ therein. The underside 962 further has notches964′ that are sized to receive the hinges 912 therein. The notches 964,964′ are sized to snappingly receive a portion of the hinges 912′, 912therein. Thus, when the anvil has been completely assembled and attachedto the trocar shaft, the staple-forming pockets in the anvil plateassembly are properly aligned (i.e., insubstantial registry) with thestaples in the stapling head of the circular stapling instrument.

FIGS. 44 and 45 illustrate another collapsible anvil support member 980that may be used to support any of the anvil plate assemblies disclosedherein. As can be seen in those Figures, the anvil support member 980includes an anvil shaft 982 that has a proximal end 984 that isconfigured to be attached to the tip of a trocar of a circular staplinginstrument. The anvil shaft 982 is configured to be attached to thetrocar tip of the surgical stapling device in a desired orientation. Theanvil shaft 982 may, for example, be configured as shown in FIG. 14 tobe attached to the trocar tip. In addition, the anvil support member 980further includes a plurality of anvil support arms 986 that arepivotally coupled to the anvil shaft 982. The anvil support arms 986 maybe configured with a detent or other latching arrangement such that whenthey are pivoted to the open position illustrated in FIG. 45, they arereleasably locked in that position. In other embodiments, no latchingarrangement is employed.

As can be seen in FIG. 45, each of the anvil support arms 986 has alatch tab 988 thereon that is configured to latch with the anvil plateassembly when the anvil plate assembly is in the open planar position. Avariety of latch tab arrangements may be employed. In one embodiment,the tabs 988 may be configured to be pressed into openings in the anvilplate assembly. One of the tabs 988 may be sized or located such that itcan only latch with a corresponding one opening or latch tab in theanvil plate assembly to properly orient the anvil plate assemblyrelative to the anvil shaft. Such arrangement serves to ensure that thestaple-forming pockets in the anvil plate assembly are properly alignedwith the staples in the stapling head when the anvil shaft has beenproperly attached to the trocar shaft in a desired orientation.

FIGS. 46-52 illustrate another expandable anvil support member 1000 thatmay be employed with the circular stapling device 10 or other circularstapling devices with the changes/modifications noted below to performvarious surgical stapling procedures. In at least one implementation,the expandable anvil support member 1000 that may be used in connectionwith an anvil plate assembly 1080 or any of the other anvil plateassembly embodiments disclosed herein.

In various embodiments, the expandable anvil support member 1000includes a central shaft 1010 that has a hollow proximal end 1012 thatis sized to receive a tip 1102 of a trocar shaft 1100 of the circularstapling instrument 10. A plurality of engagement tabs 1014 are providedin the proximal end 1012 and have a locking detent or ledge 1016 formedthereon that are designed to snap into an undercut 1104 in the trocarshaft 1100. See FIGS. 46-48. Other latching arrangements may be employedto affix the central shaft 1010 to the trocar shaft 1100. Also invarious implementations, a plurality (e.g., four) of pivot shafts 1018transversely protrude from the central shaft 1010 and define pivot axesPA-PA that are substantially transverse to the shaft axis SA-SA. Thedistal end 1019 of the central shaft 1010 is flared as shown.

An embodiment of the expandable anvil support member 1000 furtherincludes a hollow locking sleeve 1020 that is movably journaled on thecentral shaft 1010. The locking sleeve 1020 has a plurality of slots1022 that are oriented to permit the pivot bars 1018 to slidably extendtherethrough. The distal end 1024 of the locking sleeve 1020 has adeformable retention ring 1030 attached thereto that is configured tointeract with a centrally disposed hub portion 1031 that extends throughthe stapling head 20 as shown. In its initial undeformed configuration,the retention ring 1030 is located at the distal end 1033 of the centralhub 1031 and permits the trocar shaft 1100 to freely pass therethrough.As the trocar shaft 1100 is drawn in the proximal direction, the pivotshafts 1018 will contact the bottom of the slots 1022 in the lockingsleeve 1020 thereby drawing the locking sleeve 1020 in the proximaldirection as well. As the retention ring 1030 is drawn into the centralhub portion 1031, the retention ring 1030 deforms into frictionalcontact with the inside wall of the central hub 1031 to retain thelocking sleeve 1020 in position as will be discussed in further detailbelow.

In various implementations, the anvil support member 1000 furtherincludes a movable linkage assembly 1040 that comprises two pairs (onlyone pair of linkage bars 1042 are shown in the Figures) of diametricallyopposed linkage bars 1042 that are pivotally coupled to the pivot shafts1018. For example, FIGS. 46, 47, and 52 depict two diametrically opposedlinkage bars 1042 that are pivotally coupled to the central shaft 1010about the pivot shafts 1018. Each linkage bar 1042 has a notched distalend 1044 that is configured to retainingly engage a shaft cap 1050 thatis journaled over the distal end 1019 of the shaft 1010. The shaft cap1050 is sized such that it may be inserted through a specific size oftrocar cannula or other opening in the body. Each of the linkage bars1042 has a proximal end 1046 that is configured to be latched to ananvil plate assembly 1080. Any of the latching arrangements disclosedherein may be employed to latch the anvil plate assembly 1080 or any ofthe other anvil plate assemblies disclosed herein to the proximal ends1046 of the linkage bars 1042.

Various embodiments of the anvil support member 1000 further include adistal locking collar 1060 that is attached to the distal end 1022 ofthe locking sleeve 1020. FIGS. 50 and 51 illustrate one method ofmanufacturing the distal locking collar 1060. In various embodiments,the distal locking collar 1060 may comprise a hollow sleeve and whichhas a plurality of longitudinal slits 1062 equally spaced around itscircumference. See FIG. 50. As can also be seen in FIG. 50 in itsinitial “unlocked” or “unformed position” the center of the sleeve 1060may have a central outer diameter “D1” that is larger than its enddiameters “DE”. When axial forces “AF” are applied to the ends of thedistal locking collar 1060, the collar collapses axially therebyincreasing the central outer diameter (“D2” is larger than “D1”).

In use, the anvil support member 1000 and the expandable anvil plateassembly 1080 (or any of the other anvil plate assemblies disclosedherein) may be separately introduced into the patient's body through,for example, a trocar cannula or other body opening. FIG. 46 illustratesthe attachment of the anvil support member 1000 to the trocar shaft1100. As can be seen in that Figure, the anvil plate assembly 1080 hasbeen attached to the proximal ends 1046 of the linkage bars 1040. Oncethe central shaft 1010 has been attached to the trocar shaft 1100, thesurgeon may then start to draw the anvil support member 1000 proximally(“PD”) toward the stapling head 20 by rotating the knob 40 of thecircular stapling instrument. As the shaft 1010 is drawn proximally,pivot shafts 2018 will contact the bottom of the respective slot 1022from which they protrude in the locking sleeve 1020. In addition as thecentral shaft 1010 is drawn proximally, the distal locking collar 1060will be collapsed outward between the distal end 1019 of the shaft 1010and the distal end 1022 of the locking sleeve 1020. As shown in FIG. 47as the distal locking collar 1060 collapses into retaining engagementwith the notched distal ends 1044 of the linkage bars 1040 to retainthem in engagement with the shaft cap 1050. Such configurationpermanently retains the linkage bars 1040 in their expanded or deployedorientation.

The surgeon may then continue to draw the trocar shaft 1100 proximallywhich draws the anvil support member 1000 and the anvil plate assembly1080 toward the stapling head 20. As the shaft 1010 and the lockingsleeve 1020 are drawn proximally, the retention ring 1030 is biasedradially inward (arrows “R” in FIG. 47) into the central hub portion1031. As the retention ring 1030 is drawn into the central hub portion1031, the retention ring 1030 deforms into frictional contact with theinside wall of the central hub portion 1031 to retain the locking sleeve1020 in position. This embodiment may be employed to perform a varietyof surgical procedures including those procedures described above.

FIGS. 53-57 illustrate another collapsible and expandable anvil supportmember 1200 that may be effectively employed with any of the anvil plateassemblies described herein. In at least one implementation, the anvilsupport member 1200 includes a central shaft 1210 that has a distal end1212 and a proximal end 1214. The proximal end 1214 may be configured asillustrated in FIG. 14 to be releasably attached to a trocar shaft of acircular stapling instrument. In other embodiments, the proximal end1214 may be latched onto the tip of a trocar shaft as described above.In still other arrangements, the proximal end 1214 may be keyed onto thetrocar shaft to properly orient the staple support member 1200 relativeto the staple cartridge supported within the stapling head of thecircular stapling instrument. In each case, it is desirable to properlyorient the staple support member 1200 relative to the stapling head andstaple cartridge therein so that when an anvil plate assembly isattached thereto, the staple-forming-surface and staple-forming pocketstherein are properly oriented to form the staples as they are driveninto the anvil plate assembly.

As can also be seen in FIGS. 53-56, in at least one implementation, ananvil cap 1220 is attached to the distal end 1212 of the central shaft1210. The anvil cap 1220 is sized to pass through a trocar cannula orother size of opening in the body. The anvil cap 1220 may be configuredwith an arcuate dome-shaped surface 1222 to facilitate easy passagethrough the body without inadvertently injuring adjacent tissue.However, in other implementations, the anvil cap 1220 may be configuredto puncture through tissue to enable the anvil support member to be usedto perform certain procedures described above.

Various implementations of the anvil support member 1200 further includea linkage assembly 1230 that is movably journaled on the central shaft1210. In various embodiments, the linkage assembly 1230 may include twopairs of linkage bars that are pinned to the distal end of the shaft1210. More specifically, as can be seen in FIG. 56, the linkage assembly1230 includes a first pair 1232 of diametrically opposed first linkagebars 1234 that are pivotally coupled to the central shaft 1210 about afirst pivot shaft 1236 that defines a first pivot axis “PA1”-“PA1” thatis substantially transverse to the shaft axis “SA”-“SA”. The linkageassembly 1230 further includes a second pair 1240 of diametricallyopposed second linkage bars 1242 that are pivotally coupled to thecentral shaft 1210 about a second pivot axis 1244 that defines a secondpivot axis “PA2”-“PA2” that is substantially transverse to the shaftaxis “SA”-“SA”. Such arrangement permits each of the linkage bars 1234,1242 to pivot in a corresponding plane that is offset from the center ofthe shaft 1210. This arrangement permits simple rotation of the linkagebars 1234, 1242 to cross each other when expanded (FIGS. 54 and 56), butto be rotated flat along the shaft 1210 (FIG. 53) and capable of fittingdown a trocar cannula for rotation. For example, in at least oneimplementation, the diameter of the anvil cap 1220 is approximatelyslightly less than −15 mm diameter. When in the collapsed or closedposition (FIGS. 53 and 55), the anvil support member 1200 may pass downa trocar cannula that has a diameter that is approximately 15 mm. Whenin the expanded position, however, the proximal ends of the linkage barsmay open to a diameter “D” of approximately 35 mm. See FIG. 56. Ofcourse, the anvil support member 1200 may be provided in different sizesto accommodate different cannula and opening sizes without departingfrom the spirit and scope of the present invention.

Also in various implementations, each of the first latch bars 1234 has anotched distal end 1235 that is configured to latching engage acorresponding first latch feature/cavity 1224 in the anvil cap 1220 whenthe linkage assembly 1230 is in the deployed or expanded orientation.See FIG. 57. Similarly, each of the second latch bars 1242 has a notcheddistal end 1244 that is configured to latching engage a correspondingsecond latch feature/cavity (not shown) in anvil cap 1220 when thelinkage assembly 1230 is in the deployed or expanded orientation.

As illustrated in FIGS. 53 and 54 each of the first linkage bars 1234have a first proximal end 1237 that is configured to latchingly engagean anvil plate assembly of any of the types described herein. In oneimplementation, for example, the first proximal ends 1237 may have aplurality of latch detents 1239 sized to latchingly engage correspondingfirst latch openings or features in the anvil plate assembly. However,other latch arrangements of the types and construction described abovemay be employed. Similarly each of the second linkage bars 1242 have asecond proximal end 1246 that is configured to latchingly engage theanvil plate assembly. The second proximal end may have second detents1248 that are sized to latchingly engage corresponding second latchopenings or latch features in the anvil plate assembly. The first andsecond latch features may be configured to latch with the anvil plate insuch a way that the anvil plate assembly is properly oriented relativeto the stapling head of the instrument when the shaft 1210 has beenattached to the trocar shaft of the instrument.

As can also be seen in FIGS. 53 and 54, an elastomeric locking sleeve1260 is received on the linkage assembly 1230. The locking sleeve 1260may have an open ended conical shape. The bias of the locking sleeve1260 forces the first and second linkage bars 1234 and 1242 to theexpanded or open position when unconstrained. When in that collapsed orundeployed position, the biasing force generated by the locking sleeve1260 is not great enough to cause the first and second linkage bars1234, 1242 to latchingly engage the anvil cap 1250. However, when thelinkage bars 1234, 1242 are moved to their expanded or deployedorientation, the locking sleeve forms a set of rigid triangles lockingthe anvil support member 1200 and sufficiently strong to support theloads of forming staples. This embodiment may be employed to perform avariety of surgical procedures including those procedures describedabove.

FIGS. 58-63 illustrate, in diagrammatic form, a method of attaching ananvil support member 1300 to an anvil plate assembly 1350. Those ofordinary skill in the art will understand that features of the anvilsupport plate 1350 may be employed in connection with any of the anvilsupport member embodiments and any of the anvil plate assemblyembodiments disclosed herein. As can be seen in FIGS. 58-60, the anvilsupport member 1300 has a linkage assembly 1302 that comprises aplurality of linkage bars 1304. In the depicted embodiment, the linkagebars 1304 are shown in the deployed or open position. In the depictedembodiment, an elastomeric locking sleeve 1311 is received on thelinkage bars 1304 as shown in FIG. 58.

Each of the linkage bars 1304 has a magnet attached to its proximal end1306. In particular, those linkage bars 1304 that are diametricallyopposed to each other have a like-poled magnet attached thereto. Assuch, in ant least one form, two opposed linkage bars 1304 have apositively poled magnet 1308 attached thereto and the other two opposedlinkage bars 1304 have a negatively poled magnet 1310 attached thereto.See FIGS. 59 and 60. The anvil plate assembly 1350 has a staple-formingsurface 1352 thereon that has staple-forming pockets therein (not shown)that are configured to form staples as they are driven from the staplinghead of the stapling instrument to which the anvil assembly is attached.

As with the various anvil support members described above, the shaftportion 1312 of the anvil support member 1300 is configured to beattached to the trocar shaft of the circular stapling instrument.Various methods of attaching the anvil support member to the trocar in aspecific orientation (keys, locking tabs, detents, etc.) have beendisclosed. In at least one implementation, the anvil plate assembly 1350has a plurality of magnets attached thereto or embedded therein that arearranged to mate with the magnets 1308, 1310 of the staple supportmember 1300. When the anvil plate assembly 1350 is attached to an anvilsupport member 1300 that has been properly coupled to the trocar shaftof a surgical stapling instrument, the staple-forming surface 1352 ofthe anvil plate assembly 1350 is properly oriented relative to thesurgical staples within the stapling head of the instrument. As such,the negative poled magnets 1354 are oriented within the anvil plateassembly 1350 to magnetically couple to the positive poled magnets 1308attached to the anvil support member 1300 and the positive poled magnets1356 are oriented to magnetically couple to the negative poled magnets1310 on the anvil support member 1300.

FIGS. 64-70 illustrate another anvil assembly 1400 that is configurablebetween a collapsed configuration (FIGS. 67, 68, and 70) to an expandedconfiguration (FIGS. 64-66). The portions of the anvil assembly 1400 maybe sized such that when in the collapsed configuration, the anvilassembly 1400 may pass through a particular size of trocar cannula oropening of a particular size. As can be seen in the Figures, the anvilassembly 1400 has an anvil head assembly 1410 that has an anvil shaft1460 attached thereto. The Figures depict the proximal end 1462 of theanvil shaft with a square cross-section. The proximal end 1462 of theanvil shaft 1460 may have a circular cross-section. In eitherarrangement, the proximal end 1462 of the anvil shaft 1460 is configuredto be attached to the trocar of a circular stapling instrument. Thus,the proximal end 1462 of the anvil shaft 1460 may be configured as shownin FIG. 14. In other embodiments, the proximal end 1462 of the anvilshaft 1460 may have a hollow portion sized to receive the tip of thetrocar shaft therein. Locking tabs, detents, etc. may be employed toaffix the anvil shaft 1460 to the trocar shaft. See, e.g., thearrangements depicted in FIG. 48. In addition or in the alternative, theproximal end 1462 of the anvil shaft 1460 may be keyed onto the trocarshaft to properly orient the anvil head assembly 1410 relative to thestaples support in the stapling head of the stapling instrument.

As can be seen in FIGS. 64-70, the anvil head assembly 1410 includes ananvil body portion 1412 to which the anvil shaft 1430 is attached. Inparticular, the anvil shaft 1460 is attached to the anvil body portion1412 such that it protrudes from a bottom surface 1414 thereof. Theanvil body portion 1412 has a first pair 1420 of first sides 1422. Eachfirst side 1422 tapers from the bottom surface 1414 to the top surface1416 of the anvil body portion 1412 as shown. Each first side 1422 has acentrally disposed key 1424 as shown. Slidably attached to each firstside 1422 is a first anvil segment 1430. Each first anvil segment 1430may be shaped as shown in the Figures and have a keyway 1432 that issized to receive the corresponding first key 1424 therein. Each firstanvil segment 1430 has a staple-forming surface 1434 thereon that has aninner line 1435 and an outer lined 1436 of staple-forming pockets 1438.See FIG. 70. As can be seen in FIGS. 68 and 70 each of the first anvilsegments 1430 are configured to slide in the proximal direction “PD”relative to the anvil body portion 1412 when the anvil assembly 1400 isin the collapsed orientation.

As can be further seen in FIGS. 64-70, the anvil body portion 1412 has asecond pair 1440 of second sides 1442. Each second side 1442 tapers fromthe bottom surface 1414 to the top surface 1416 of the anvil bodyportion 1412 as shown. Each second side 1442 has a centrally disposedsecond key 1444 as shown. Slidably attached to each second side 1442 isa second anvil segment 1450. Each second anvil segment 1450 may beshaped as shown in the Figures and have a keyway 1452 that is sized toreceive the corresponding second key 1444 therein. Each second anvilsegment 1450 has a staple-forming surface 1454 thereon that has an innerline 1455 and an outer line 1456 of second staple-forming pockets 1458.See FIG. 70. As can be seen in FIGS. 68 and 70 each of the second anvilsegments 1450 is configured to slide in the distal direction “DD”relative to the anvil body portion 1412 when the anvil assembly 1400 isin the collapsed orientation.

To install the anvil assembly 1400, the surgeon orients the first anvilsegments 1430 in the down or proximal direction and the second anvilsegments 1450 are oriented in the up or distal direction relative to thebody portion 1412. Such first or collapsed orientation provides theanvil head 1410 with its smallest cross-sectional profile. That is, theanvil head assembly 1410 has an “overall width” that is measured alongan axis that is substantially perpendicular to the shaft axis “SA-SA”.When in the first or collapsed orientation, the overall width has amagnitude “D1” as shown in FIG. 71. When the anvil head assembly 1410 isin the second or expanded orientation, the magnitude of the overallwidth (designed as D2 in FIG. 72) is greater than magnitude of theoverall width when the anvil head assembly is in the first or collapsedorientation. When in the collapsed orientation, the anvil head 1410 maypass through a particular size of opening or trocar cannula. The anvilshaft 1460 may be attached to the trocar shaft of the instrument priorto insertion into the patient or after the anvil assembly 1400 has beeninserted into the patient. Thereafter, the surgeon then moves the secondanvil segments 1450 downward or in the proximal direction “PD” and thefirst anvil segments 1430 are moved up or in the distal direction “DD”.The motions may be staggered so that the second anvil segments 1450 aremoved down in the proximal direction first and the first anvil segments1430 are moved up in the distal direction and lock into the second anvilsegments 1450. Such arrangement creates a single supported firingplatform 1470 that the staples can react against. The instrument maythen be fired. After the instrument has been fired, the second anvilsegments 1450 may be moved up in the distal direction and the firstanvil segments 1430 may be moved down in the proximal direction toreturn the anvil head 410 to the collapsed configuration. When in thecollapsed configuration, the anvil assembly 1400 may be more easilyremoved from the target tissue.

The various embodiments of the present invention represent a vastimprovement over prior circular staple arrangements and anvil assembliestherefor. While several embodiments of the invention have beendescribed, it should be apparent, however, that various modifications,alterations and adaptations to those embodiments may occur to personsskilled in the art with the attainment of some or all of the advantagesof the invention. For example, according to various embodiments, asingle component may be replaced by multiple components, and multiplecomponents may be replaced by a single component, to perform a givenfunction or functions. This application is therefore intended to coverall such modifications, alterations and adaptations without departingfrom the scope and spirit of the disclosed invention as defined by theappended claims.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialsdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

The invention which is intended to be protected is not to be construedas limited to the particular embodiments disclosed. The embodiments aretherefore to be regarded as illustrative rather than restrictive.Variations and changes may be made by others without departing from thespirit of the present invention. Accordingly, it is expressly intendedthat all such equivalents, variations and changes which fall within thespirit and scope of the present invention as defined in the claims beembraced thereby.

1. An anvil plate for a surgical stapling instrument, said anvil platecomprising a plurality of anvil plate segments movably interconnectedand reconfigurable from a first orientation wherein said anvil platesegments may be inserted through a cannula opening as a unit and thenreconfigured into a second orientation in the form of a substantiallyplanar anvil plate assembly that has a diameter that is larger than saidcannula opening.
 2. The anvil plate of claim 1 wherein said plurality ofanvil plate segments are supported on a flexible ring member that isconfigurable between said first orientation to said second orientation.3. The anvil plate of claim 2 wherein said flexible ring member isfabricated from an elastomeric material and said plurality of anvilplate segments are fabricated from metal material.
 4. The anvil plate ofclaim 1 wherein said plurality of anvil plate segments are coupledtogether by a plurality of hinges.
 5. The anvil plate of claim 4 whereinsaid plurality of anvil plate segments comprises four arcuate platesegments coupled by said hinges in end-to-end fashion such that whensaid arcuate plate segments are in said first orientation, said fourarcuate plate segments may be substantially stacked on top of eachother.
 6. The anvil plate of claim 5 wherein each said arcuate platesegment has an outer configuration of staple formation pockets and aninner configuration of staple formation pockets that are oriented toform an outer annular ring of staple formation pockets and an innerannular ring of staple formation pockets, respectively when said annularplate is in said substantially planar orientation wherein said stapleformation pockets in said inner annular ring of staple formation pocketsare staggered from said staple pockets in said outer annular ring ofstaple formation pockets.
 7. The anvil plate of claim 5 furthercomprising a flexible tether threadably engaging each of said arcuateplate segments such that said arcuate plate segments may be insertedthrough said cannula opening in an end-to end fashion wherein saidarcuate plate segments do not form an annular plate assembly and thendrawn together to form said annular plate assembly by applying anactuation motion to said flexible tether to draw a free end of one ofsaid arcuate plate segments into abutting contact with another free endof another of said arcuate plate segments to form said annular plateassembly.
 8. The anvil plate of claim 1 wherein said plurality of anvilplate segments are movably coupled together by a plurality of springclips.
 9. The anvil plate of claim 8 wherein each said anvil platesegment comprises an arcuate plate segment having two ends wherein eachsaid end has an attachment joint configured to slidably mate with thejoint formation on an adjacent anvil plate when said plurality of anvilplates form said annular anvil plate assembly.
 10. The anvil plate ofclaim 1 wherein each said anvil plate segment has a forming surface andwherein each said attachment joint has an attachment tab portion that issubstantially parallel to said forming surface.
 11. An anvil for asurgical stapling instrument, comprising: a plurality of anvil platesmovably coupled together for selective movement between non-planarorientations and a substantially planar orientation wherein saidplurality of anvil plates form an annular anvil plate assembly; and ananvil support member configured for attachment to said anvil plateassembly to retain it in said substantially planar orientation.
 12. Theanvil of claim 11 wherein said plurality of anvil plates are coupled toa flexible ring member that is configurable between said non-planarorientations and said substantially planar orientation.
 13. The anvil ofclaim 12 wherein said flexible ring member is fabricated from anelastomeric material and said plurality of anvil plates are fabricatedfrom metal material.
 14. The anvil of claim 11 wherein said plurality ofanvil plates are coupled together by a plurality of hinges.
 15. Theanvil of claim 14 wherein said plurality of anvil plates comprises fourarcuate plate segments coupled by said hinges in end-to-end fashion suchthat when said arcuate plate segments are in a first one of saidnon-planar orientations, said four arcuate plate segments may besubstantially stacked on top of each other and when said arcuate platesegments are in another of said non-planar orientations, two of saidarcuate plate segments are stacked on top of another two of said arcuateplate segments.
 16. The anvil of claim 15 wherein each said arcuateplate segment has an outer configuration of staple formation pockets andan inner configuration of staple formation pockets that are oriented toform an outer annular ring of staple formation pockets and an innerannular ring of staple formation pockets, respectively when said annularplate assembly is in said substantially planar orientation wherein saidstaple formation pockets in said inner annular ring of staple formationpockets are staggered from said staple pockets in said outer annularring of staple formation pockets.
 17. The anvil of claim 15 furthercomprising a flexible tether threadably engaging each of said arcuateplate segments such that said arcuate plate segments may be insertedthrough an opening in an end-to end fashion wherein said arcuate platesegments do not form an annular plate assembly and then drawn togetherto form said annular plate assembly by applying an actuation motion tosaid flexible tether to draw a free end of one of said arcuate platesegments into abutting contact with another free end of another of saidarcuate plate segments to form said annular plate assembly.
 18. Theanvil of claim 11 wherein said plurality of anvil plates are movablycoupled together by a plurality of spring clips.
 19. The anvil of claim18 wherein each said anvil plate comprises an arcuate plate segmenthaving two ends wherein each said end has an attachment joint configuredto slidably mate with the joint formation on an adjacent anvil platewhen said plurality of anvil plates form said annular anvil plateassembly.
 20. The anvil of claim 19 wherein each said anvil plate has aforming surface and wherein each said attachment joint has an attachmenttab portion that is substantially parallel to said forming surface.